Thousands of tons of contaminated soil excavated from the site of the new Twins ballpark was improperly placed in a flood plain last summer, and the stadium's owner estimates it now could cost up to $1 million to correct the problem.

The Minnesota Ballpark Authority said it learned only last month that 30,000 cubic yards of dirty soil was not deposited inside a lined Burnsville landfill, as ordered by the Minnesota Pollution Control Agency. The dirt -- contaminated with petrochemicals from downtown industrial sites and parking areas -- was instead diverted by Waste Management Inc. to an area near but outside the lined facility so the company could use it to build a levee to expand its 220-acre landfill on the Minnesota River.

That plan was put on hold when officials from the MPCA and Dakota County found out about the diversion. The county has threatened fines and possible prosecution against the company if the soil is not moved.

The large pile of dirt, equivalent to 2,800 dump-truck loads, has been sitting in a flood plain near the river since June while the company, government agencies and the Ballpark Authority wrangle over disposing of the dirt and who should pay for moving it a second time.

"It's a huge concern," said Ed Hunter, the Baseball Authority's project manager. "We thought it had been taken care of and put in a lined facility."

The 8-acre tract from which the soil was removed was the site of a number of industrial uses, including old rail lines and auto dealerships over the years. As a result, much of area is contaminated.

Hunter said the Baseball Authority identified seven hot spots at the site that needed special attention.

The soil dumped near the Burnsville landfill is not considered hazardous, but the Ballpark Authority is concerned it might be on the hook to pay for the removal and could face liability if the soil is used improperly.

"This is dirty dirt," Hunter said. "It is not clean. It needs to be disposed of properly."

Left hand, right hand

Part of the confusion surrounding the dirt stems from the fact that the soil came under the jurisdiction of two different units at the MPCA -- and the two departments did not communicate with one another.

Waste Management believes it had permission to use dirt of the quality of the ballpark soil for its levee by the MPCA's solid waste unit, which oversees permits for landfill sites.

But the MPCA unit that handles petroleum-contaminated soil issues reviewed the Ballpark Authority's disposal plan in 2007 and declared that any soil taken from the site had to be disposed of inside a qualified lined landfill and thus could not be used for any other purpose.

MPCA officials acknowledge that the two departments did not talk to one another, so neither realized they were working at cross-purposes.

"The different programs came at it from different angles," said Tim Scherkenbach, an assistant commissioner at the MPCA. "That's something that we need to work on."

Scherkenbach said that regardless of the bureaucratic mix-up, Waste Management should not have placed the soil outside the lined facility in a flood plain.

"That's what immediately set off the alarms for us," Hunter said. "Nobody in their wildest dreams ever considered that they were going to stick it in a flood plain."

Drawing up new plans

Mortenson Construction, which is in charge of building the ballpark and hiring the subcontractors, including the dirt haulers, did not return phone calls seeking comment.

Waste Management maintains that it diverted the dirt because its operating permit from the MPCA allows it to use incoming dirt for its levee construction as long as it meets acceptable contamination levels, which this soil did.

However, because of possible litigation, the company did not want to discuss when, or if, it was told that the ballpark dirt had a specific MPCA action plan regarding its disposal.

"Waste Management has a permit to build a levee," said Geoff Strack, a senior engineer at the MPCA. "But this action plan [for the ballpark dirt] trumps everything. My understanding is that they should have known that."

The Baseball Authority said that order was part of the contract that Mortenson, the hauler and Waste Management signed to dispose of the dirt.

In a letter this month to Dakota County, Waste Management said that it will move the dirt into the lined landfill and that it will submit a new plan to the MPCA regarding its $2 million levee building plan.

The company estimates it could take five weeks to move this and other stockpiled dirt into the lined landfill while the MPCA rules on its new plans.

"Obviously, there was some miscommunication," said Strack, who recently took over the ballpark soils case for the MPCA. "Nothing about this situation is normal. We're going to look at everything again."